1. Field of the Invention
The invention relates to an adjustable pressure relief valve or to an adjustable pressure relief valve system for generating a pressure output signal corresponding to a certain input value or signal in the valve connection area.
2. Discussion of the Background
Such pressure relief valves are known in various designs and, among other things, direct control or adjustment by precontrol can be performed. Pressure relief valves are also controlled by so-called proportional magnets, i.e., by a controllable direct voltage magnet that usually works in oil and converts an electrical signal into a proportional force that acts on the valve element of the pressure relief valve. With this type of action, a pressure relief valve with good adaptability is successfully incorporated in hydraulic control loops, and use is made of the advantage that the adjusted magnetic force remains constant over the entire control range.
However, the disadvantage of these previous attempts is that the pressure relief valves in question often had to be individually designed and constructed for different applications, and then a relatively expensive structural design was necessary. This design, matched individually to the application, results in a very limited flexibility with respect to the application possibilities of such valves in hydraulic systems of the most varied functions and requirements. Consequently, also the quantities of these valves remained limited each time. It is true that it was attempted to combine details of different basic pressure valve designs to make the production process more economical. But in known designs, this integration of the individual parts into other functional groups was able to be performed only at great expense in some cases.